Calculation of Inductor Current and Voltage

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Calculation of Inductor Current and Voltage [Copy link]

If there is coupling between the magnetic fields of the inductors, the expression for the total inductance becomes slightly more complicated. For the simple case of two inductors in series, the expression is as follows:

Series inductance, Ltotal = L1 + L2 ± 2M (2.11)

where M is the mutual inductance caused by the interaction of the two magnetic fields (note: +M is the case when the two magnetic fields are in the same direction, -M is the case when the two magnetic fields are in opposite directions).

If you want to know how to calculate the inductor current and voltage, let's first understand what an inductor is and how the inductor coil is connected in a circuit. Dongguan Xinyong Electronics brings you a detailed introduction to the calculation of the inductor current and voltage.

In a circuit, when current flows through a conductor, an electromagnetic field is generated. The magnitude of the electromagnetic field divided by the magnitude of the current is the inductance. The definition of inductance is L=phi/i, and the unit is Weber. Inductance is the ratio of the magnetic flux of the wire to the current that produces the alternating magnetic flux inside and around the wire when an alternating current passes through the wire. Inductance is a physical quantity that measures the ability of a coil to generate electromagnetic induction. When a current is passed through a coil, a magnetic field is generated around the coil, and magnetic flux passes through the coil. The greater the power supplied to the coil, the stronger the magnetic field and the greater the magnetic flux passing through the coil.

When an inductor is connected to a circuit, there are two main ways: series connection and parallel connection. When several inductors are connected to form a circuit, their total inductance is similar to the total resistance of several resistors connected in series and parallel. When there is no interaction between the magnetic fields of the inductors, the following formula is used for calculation: When

an inductor is used in a circuit, there are many data to be calculated, and the calculation of the inductor current and voltage generally refers to the calculation of the inductor voltage, because there is no inductor current to calculate when the inductor is used. Here are some common calculation formulas for inductor applications:

1. Inductor impedance calculation formula

Experiments have shown that inductive reactance is proportional to inductance and frequency. If inductive reactance is represented by XL, inductance is represented by L, and frequency is represented by f, then

XL = 2πfL

The unit of inductive reactance is ohm. If you know the frequency f of the alternating current and the inductance L of the coil, you can use the above formula to calculate the inductive reactance.

2. Calculation formula of inductor voltage

Formula: U=Ldi/dt

Some LC tank circuits use air-core coils in their resonant circuits, as shown in the figure. Note that the two adjacent inductors are arranged perpendicular to each other. In specific wireless circuit design, this arrangement is cumbersome, but it is a way to reduce the interaction between each magnetic field. In general, if the coils are very similar, the following two principles should be followed:

(1) When the axes of the two coils are parallel to each other, the interaction is maximum.

(2) When the axes of the two coils are perpendicular to each other, the interaction is minimum.

When the axes of the two coils are along the same straight line, the interaction depends on the spacing between the two coils.